“Reaction engine” experiment

How can we make a re­ac­tion en­gine? We’ll only need a glass jar with a lid, ethyl al­co­hol and a lit­tle in­ge­nu­ity!

Safe­ty pre­cau­tions

Ob­serve safe­ty rules when work­ing with fire.

Warn­ing! Only un­der adults su­per­vi­sion.

Reagents and equip­ment:

• glass jar;
• lid with hole;
• 96% al­co­hol (50 ml).

Step-by-step in­struc­tions

We pour al­co­hol into the glass jar and seal it with a lid with a hole in the cen­ter with even edges. The jar is shak­en so the al­co­hol evap­o­rates bet­ter. We ig­nite the al­co­hol fumes by the hole. The en­gine starts to roar!

Pro­cess­es de­scrip­tion

It’s easy to make a sim­ple im­pulse re­ac­tion en­gine from an or­di­nary jar. Al­co­hol will be the fuel. But the se­cret of this en­gine is the lid with the hole! The pro­por­tions of the hole need to be cho­sen pre­cise­ly for each con­tain­er: if we make it big­ger, the fuel will run out quick­ly, but if we make it small­er, the flame will go out from a lack of oxy­gen. if the ge­om­e­try of the hole and the size of the con­tain­er is cor­rect, the fuel will burn in puls­es. With each pulse, it spits out a tongue of flame, and then sucks the air through the hole into the re­gion of ex­pan­sion that sud­den­ly ap­pears, re­ceiv­ing a new por­tion of ox­i­diz­er. The en­gine will func­tion un­til the fuel runs out or the jar cracks from over­heat­ing.